Homer disappoints Lisa on her birthday when he gives her a thoughtless present. He realizes that he knows little about her and decides to hire private detective Dexter Colt to spy on her. Colt compiles a report, the information from which helps Homer bond with his daughter. However, Colt soon demands to be paid $1000, which Homer refuses. In retaliation, Colt vandalises an animal research lab and steals all the animals, leaving behind several clues that implicate Lisa. Homer and Lisa go on the run as fugitives and end up at a circus, where they meet Colt. He tries to kill Homer, but Lisa saves him. Later, Colt is arrested and Lisa exonerated. She finally receives the present she wanted from Homer.